JP2022153990A - Fixing device and image forming apparatus - Google Patents

Abstract

To provide means that prevents damage to a fixing member.SOLUTION: A fixing device has a rotatable belt-like fixing member, and a regulation member (6) that regulates a side end in a rotation direction of the stretched fixing member. The regulation member (6) has: a guide part (68) that is in contact with part of an inner peripheral surface of the fixing member in the rotation direction; a regulation part (61) that regulates the movement of the side end of the fixing member with which the guide part (68) is in contact; and an upstream inclined part (62) that is provided to extend to an upstream side of the regulation part (61) in the rotation direction and is formed with an inclined plane inclined in a direction separating from the fixing member. In the rotation direction, an end point (64) of the inclined plane of the upstream inclined part (62) is provided on the upstream side of a starting point of the guide part (68).SELECTED DRAWING: Figure 8

Description

The present invention relates to a fixing device having a rotatable belt and an image forming apparatus having the fixing device.

A conventional fixing device has a configuration in which a non-printing area at the end of a belt serving as a fixing member is inserted into a cap-shaped flange, and the inner peripheral portion of the flange is shaped such that the inner diameter gradually decreases until it reaches the belt regulating surface. (See Patent Document 1, for example).

JP-A-2002-323821

However, in the prior art, when the belt side and the flange restricting surface are not completely parallel due to mounting tolerances, the flange supporting the inner surface and the side of the belt as a member for regulating the deviation of the belt as the rotating fixing member has a problem. There is a problem that the belt may be damaged by the bias force of the belt.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem, and to suppress breakage of the fixing member.

Therefore, the present invention has a rotatable belt-shaped fixing member and a regulating member that regulates a side end portion of the stretched fixing member in the rotational direction, and the regulating member a guide portion that contacts a portion of the inner peripheral surface of the fixing member; a regulation portion that regulates movement of the side end portion of the fixing member that contacts the guide portion; an upstream inclined portion provided to extend and formed with an inclined surface inclined in a direction away from the fixing member, wherein the end point of the inclined surface of the upstream inclined portion in the rotational direction is the guide portion; is provided on the upstream side from the starting point of the

According to the present invention configured in this way, it is possible to obtain the effect of being able to suppress damage to the fixing member.

FIG. 1 is a schematic cross-sectional side view showing the configuration of an image forming apparatus according to a first embodiment; Schematic side sectional view showing the configuration of a fixing device in the first embodiment. Explanatory drawing showing the configuration of the fixing roller and pressure roller in the first embodiment. FIG. 2 is a cross-sectional view showing the configuration of the fixing belt in the first embodiment; Explanatory drawing showing the configuration of the nip forming member in the first embodiment. 1 is an exploded perspective view of a planar heating element in a first embodiment; FIG. Top view of the planar heating element in the first embodiment FIG. 2 is a perspective view of the belt regulating member in the first embodiment; Explanatory drawing of the fixing belt and the belt regulating member in the first embodiment. Explanatory drawing of the apex of the tapered portion in the first embodiment Explanatory drawing of printing durability of the fixing belt in the first embodiment Explanatory drawing of the action of the belt regulating member in the first embodiment. Explanatory diagram of the operation of the fixing belt in the first embodiment. A perspective view of a belt regulating member in the second embodiment. Explanatory drawing of the apex of the tapered portion in the second embodiment Explanatory drawing of printing durability of the fixing belt in the second embodiment

Hereinafter, embodiments of a fixing device and an image forming apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic side sectional view showing the configuration of an image forming apparatus according to the first embodiment. FIG. 1(a) is a schematic side cross-sectional view of the entire image forming apparatus, and FIG. 1(b) is a schematic side cross-sectional view of a developing device provided in the image forming apparatus.

In FIG. 1, an image forming apparatus 10 performs printing by forming a toner image as a developer image on a medium in accordance with a print job (print data) received from a host device. is. Note that the image forming apparatus 10 may be a color printer that forms toner images as multiple color developers, or may be a monochrome printer that forms single-color toner images.

The image forming apparatus 10 includes a developing device 13 that forms a toner image on a printing medium P conveyed in a medium conveying direction indicated by an arrow A in FIG. a device 11;

The developing device 13 charges an image carrier 14 such as a photosensitive drum or a photosensitive belt with a charging member 15 , forms an electrostatic latent image with a latent image forming means 16 , and develops the latent image with a developing means 17 . A toner image is formed by developing toner, and the toner image is transferred from the image carrier 14 to a recording medium P made of plain paper or special paper as a fixing material by a transfer member 18 .

The fixing device 11 heats and presses the print medium P transported from the developing device 13 to fuse the toner, and fixes the toner transferred to the print medium P. FIG.

In color image forming apparatuses such as color copiers, color printers, and color facsimiles, toners of two or more colors are transferred onto a recording medium P, so four pairs of developing devices 13 are provided as shown in FIG. and a transfer member 18 .

FIG. 2 is a schematic side sectional view showing the configuration of the fixing device in the first embodiment.

In FIG. 2, the fixing device 11 heats and presses the print medium P transported in the medium transport direction indicated by the arrow A in the figure to fuse the toner 9 and fix the toner 9 transferred to the print medium P. A fixing roller 1, a fixing belt 2, supports 3a and 3b, a planar heating element 4, pressure members 5a and 5b, a belt regulating member 6, a nip forming member 7, and a pressing member 7. and a pressure roller 8 .

The fixing belt 2 as a fixing member heats the print medium P and the toner 9 to fix the toner 9 onto the print medium P. As shown in FIG. The fixing belt 2 is an endless belt rotatable in the direction of belt rotation indicated by an arrow B in the figure, and supports the fixing roller 1, the belt regulating member 6, the nip forming member 7, and the planar heating element 4. It is rotatably stretched by the body 3a.

Binder resins used in toner 9 include polystyrene, styrene/propylene copolymer, styrene/vinyl naphthalene copolymer, styrene/methyl acrylate copolymer, polyester polymer, polyurethane polymer, and epoxy polymer. , aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins and the like can be used, and these can be used singly or in combination. Wax may be added to the toner 9 for the purpose of preventing offset during fixation. As the wax in this case, polyethylene wax, propylene wax, carnauba wax, various ester waxes, and the like are used. be able to.

A planar heating element 4 as a heating member heats the fixing belt 2 and is sandwiched between the support 3a and the support 3b.

With the rotation center of the support 3a as a fulcrum, the total pressure load applied to the fixing belt 2, that is, the total pressure load applied by the pressure member 5a such as a spring to the support 3b is determined by the slidability between the support 3a and the fixing belt 2. is about 2 kg·f at maximum so as not to worsen the

Also, the nip forming member 7 is pressurized by a pressurizing member 5b such as a spring.

The fixing roller 1 is pressed against the pressure roller 8 with a load of about 20 kg·f at maximum with the fixing belt 2 interposed therebetween.

The nip forming member 7 is arranged at a position facing the pressure roller 8 with the fixing belt 2 interposed therebetween, and forms a contact portion (nip portion) between the fixing belt 2 and the pressure roller 8 . The print medium P transported in the medium transport direction passes through a nip formed between the fixing belt 2 and the pressure roller 8 .

Further, a temperature sensor as a temperature detecting means is arranged in contact with the outer surface or the inner surface of the fixing belt 2 or in a non-contact manner with a minute gap.

The supports 3a and 3b are made of a highly thermally conductive and workable metal such as aluminum or copper, or alloys containing these as main components, or highly heat-resistant and rigid iron, iron-based alloys, stainless steel, or the like. ing.

The supports 3a and 3b and the planar heating element 4 are integrated by being pressed against the fixing belt 2, and serve as a fixed member to allow the fixing belt 2, which is rotated by rotational driving, to slide.

The surface of the planar heating element 4 that contacts the supports 3a and 3b is flat, and a ceramic heater, a stainless steel heater, or the like is used. Further, the planar heating element 4 is arranged downstream of the support 3a in the belt rotation direction in order to increase the heat transfer efficiency between the support 3a and the fixing belt 2. As shown in FIG.

The belt regulating member 6 as a regulating member regulates the shift (movement) of the side end portion of the fixing belt 2 in the rotation direction, and the fixing belt in the axial direction of the fixing roller 1 (direction orthogonal to the belt rotation direction). 2 are opposed to each other with the fixing belt 2 interposed therebetween. Details of the belt regulating member 6 will be described later.

FIG. 3 is an explanatory diagram showing the configuration of the fixing roller and pressure roller in the first embodiment.

The fixing roller 1 and pressure roller 8 shown in FIG. 2 are composed of an elastic layer 20 and a metal core 19, as shown in FIG. 3(a). Also, the pressure roller 8 may have a release layer 21 formed on the elastic layer 20 as shown in FIG. 3(b).

The elastic layer 20 is generally made of a highly heat-resistant rubber material such as silicon rubber, sponge-like silicon rubber, or fluororubber. A metal pipe or shaft made of aluminum, iron, stainless steel, or the like is used for the core metal 19 in order to maintain a certain rigidity.

The fixing roller 1 is rotationally driven in the direction indicated by arrow B in FIG. 2, and the pressure roller 5 is rotationally driven in the direction indicated by arrow C in FIG.

FIG. 4 is a sectional view showing the construction of the fixing belt in the first embodiment.

As shown in FIG. 4, the fixing belt 2 is, for example, a thin substrate 22a (in the case of a substrate made of nickel, polyimide, stainless steel, etc., the thickness is preferably about 30 to 150 μm in order to achieve both strength and flexibility). ) above, as the elastic layer 22b, silicon rubber (preferably 50 to 300 μm in thickness to achieve both low hardness and high thermal conductivity) or fluorine resin (preferably thick to achieve both reduction in thickness due to abrasion and high thermal conductivity is 10 to 50 μm), and a release layer 22c is provided on the elastic layer 22b.

The release layer 22c is made of a resin having high heat resistance and low surface free energy after molding, such as PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane), FEP (perfluoroethylene-propene copolymer), and the like. A typical fluororesin (thickness preferably 10 to 50 μm) can be used.

FIG. 5 is an explanatory diagram showing the structure of the nip forming member in the first embodiment.

In FIG. 5, the nip forming member 7 has a metal core 23 and an elastic layer 24 .

A metal shaft made of aluminum, iron, stainless steel, or the like is used for the cored bar 23 in order to maintain a certain rigidity.

The elastic layer 24 is generally made of a highly heat-resistant rubber material such as silicon rubber, sponge-like silicon rubber, or fluororubber, and may be coated with a silicon-based or fluorine-based coat or film.

At this time, the total pressing load by the pressing member 5b shown in FIG. 2 is about 10 kg·f at maximum so as not to deteriorate the slidability between the nip forming member 7 and the fixing belt 2. FIG.

FIG. 6 is an exploded perspective view of the planar heating element in the first embodiment, and FIG. 7 is a top view of the planar heating element in the first embodiment.

In FIGS. 6 and 7, the planar heating element 4 is formed by forming a thin glass film as an electrical insulating layer 29b on a substrate 26 such as SUS430, and then coating powder of nickel-chromium alloy or silver-palladium alloy on it. A resistive heating element 27 is formed in a paste form by screen printing, and electrodes 28 are formed at the ends from a metal such as silver that is chemically stable and has low electrical resistance, or a high melting point metal such as tungsten. Alternatively, one protected by a protective layer 29a made of a representative fluorine-based resin such as PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane), FEP (perfluoroethylene-propene copolymer), or the like is used.

FIG. 8A is a perspective view of the belt regulating member in the first embodiment, FIG. 9 is an explanatory diagram of the fixing belt and the belt regulating member in the first embodiment, and FIG. FIG. 4 is an explanatory diagram of a taper portion vertex; 9A and 9B are explanatory diagrams in the case where the regulating member 6 regulates the deviation of the fixing belt 2, and are perspective views of the fixing belt 2. FIG.

As shown in FIGS. 8A, 9, and 10A, the belt regulating member 6 includes a belt regulating surface 61, extensions 62 and 66, edges 63 and 65, and a tapered portion apex 64. , 67, a belt running surface 68, a belt running surface inlet 68a, and a belt running surface outlet 68b.

The belt running surface 68 as a guide part contacts a part of the inner circumferential surface of the fixing belt 2 in the belt rotation direction indicated by the arrow B and guides the fixing belt 2 .

As shown in FIG. 9, the belt running surface 68 is a contact surface that contacts the inner peripheral surface of the rotating fixing belt 2, and is formed in a curved shape. Therefore, the fixing belt 2 rotates while the inner peripheral surface of the fixing belt 2 comes into contact with the belt running surface 68 and slides.

The belt running surface entrance 68a is the starting point of the belt running surface 68 in the belt rotation (running) direction indicated by the arrow B. As shown in FIG.

The belt running surface outlet 68b is the end point of the belt running surface 68 in the belt rotation (running) direction indicated by the arrow B. As shown in FIG.

The belt regulating surface 61 as a regulating portion regulates the movement of the side end portion of the fixing belt 2 in contact with the belt running surface 68 in the belt rotation direction indicated by the arrow B. As shown in FIG.

The belt regulating surface 61 is formed perpendicularly (perpendicularly) to the curved belt running surface 68 and regulates the movement of the fixing belt 2 by coming into contact with the side edge of the rotating fixing belt 2 in the rotational direction. It is a wall that

The extension portion 62 as an upstream inclined portion is provided so as to extend upstream of the belt regulating surface 61 in the belt rotation (running) direction indicated by the arrow B, and the inclined surface inclined in the direction away from the fixing belt 2 is tapered. It is formed in

The inclined surface of the extension portion 62 is continuous with the belt regulating surface 61 and is formed so as to be inclined in the direction away from the fixing belt 2 from the downstream side to the upstream side in the belt rotation direction.

The extension portion 66 as the downstream inclined portion is provided so as to extend downstream of the belt regulating surface 61 in the belt rotation (running) direction indicated by the arrow B, and the inclined surface inclined in the direction away from the fixing belt 2 is tapered. It is formed in

The inclined surface of the extension portion 66 is continuous with the belt regulating surface 61 and is formed so as to be inclined away from the fixing belt 2 from the upstream side to the downstream side in the belt rotation direction.

A tapered portion apex 64 is a boundary between the belt regulating surface 61 and the extension portion 62, and is an end point of the extension portion 62 in the belt rotation (running) direction indicated by the arrow B. As shown in FIG. The edge portion 63 is the starting point of the extension portion 62 in the belt rotation (running) direction indicated by the arrow B. As shown in FIG.

The tapered portion apex 67 is the boundary between the belt regulating surface 61 and the extension portion 66, and is the starting point of the extension portion 66 in the belt rotation (running) direction indicated by the arrow B. As shown in FIG. The edge portion 65 is the end point of the extension portion 66 in the belt rotation (running) direction indicated by the arrow B. As shown in FIG.

Since the tapered extensions 62 and 66 are formed at the ends of the belt regulating member 6 in the belt rotation direction, the attachment angle of the belt regulating member 6 is perpendicular to the surface of the fixing belt 2 . Even if not, the fixing belt 2 can run smoothly without contacting the edge 63 on the upstream side and the edge 65 on the downstream side in the rotation direction of the fixing belt 2 .

In this embodiment, the tapered extension portion 62 on the upstream side in the belt rotation direction forms a tapered portion apex 64 at the boundary of the belt restricting surface 61 , and the tapered portion apex 64 is the most upstream portion of the belt running surface 68 . It is located further upstream than the belt running surface entrance 68a.

That is, in the belt rotation direction, the tapered portion apex 64, which is the end point of the inclined surface of the extension portion 62, is provided upstream from the belt running surface entrance 68a, which is the starting point of the belt running surface 68. As shown in FIG.

Further, the tapered extension 66 on the downstream side in the belt rotation direction forms a tapered portion apex 67 at the boundary of the belt restricting surface 61 , and the tapered portion apex 67 is the most downstream belt running surface of the belt running surface 68 . It is at the same position as the exit 68b.

The operation of the configuration described above will be described.

First, an outline of print processing performed by the image forming apparatus will be described with reference to FIG. Note that the print processing is performed based on a print processing program stored in a memory or the like by the control unit of the image forming apparatus 10 .

The control unit of the image forming apparatus 10 receives print data (print job) as a print command from an external device via a communication line. Upon receiving the print data, the control unit controls the paper feed motor, separates and feeds the print medium P one by one, and further conveys it to the developing device 13 by the conveying rollers in accordance with the image forming timing.

At this time, the controller controls the developing device 13 to form a toner image.

First, the controller rotates the image carrier 14 of the developing device 13 and uniformly charges the surface of the image carrier 14 with the charging member 15 . The control section selectively exposes the surface of the charged image carrier 14 according to the print data by the latent image forming means 16 to form an electrostatic latent image, and then develops the image carrier 14 by the developing means 17. Toner is supplied to develop the electrostatic latent image formed on the surface of the.

The controller controls the transfer voltage and the like of the transfer member 18 to transfer the toner image developed on the surface of the image carrier 14 onto the print medium P conveyed in the medium conveyance direction indicated by the arrow A in FIG.

The print medium P onto which the toner image has been transferred by the developing device 13 is conveyed in the medium conveying direction, and the toner image of each color is transferred by the developing device performing the same developing process, and all the toner images necessary for image formation are formed. After being transferred, it is conveyed to the fixing device 11 .

The control unit controls the fixing device 11, rotates the fixing belt 2 shown in FIG. 2, and fixes the toner transferred to the print medium P by heat and pressure.

After that, the control unit conveys the print medium P in the medium conveying direction, ejects it outside the apparatus, and ends the printing process.

2, 8(a), 9, and 10, the action of the belt regulating member 6 of the fixing device 11 will be described based on the explanatory view of the action of the belt regulating member in the first embodiment shown in FIG. to explain.

In FIG. 12, a belt regulating member 6L and a belt regulating member 6R are arranged at both left and right ends of the fixing belt 2, respectively.

The fixing belt 2 is rotationally driven to generate a biasing force, and probabilistically biases to either the left or right side, and hits the belt regulating surface of one of the belt regulating members 6L and 6R, and the biasing of the fixing belt 2 is stopped. Thus, the deviation of the fixing belt 2 is regulated by the belt regulating members 6L and 6R.

Ideally, the belt regulating members 6L and 6R should be mounted perpendicular to the horizontal axis in the drawing parallel to the surface of the fixing belt 2 (parallel to the vertical axis in the drawing). installed at either + or - side angle.

The mounting angle at this time is such that the direction in which the upstream sides of the belt regulating member 6L and the belt regulating member 6R approach is the + side, and the direction in which they separate is the - side.

The breaking strength of the fixing belt 2 is the highest when the mounting angles of the belt regulating members 6L and 6R are vertical (±0).

However, as the mounting angles of the belt regulating members 6L and 6R increase toward the + side and - side, the breaking strength of the fixing belt 2 decreases.

Next, the action of the belt regulating member 6 will be described with reference to FIGS. 8, 10 and 11. FIG.

The belt regulating member 6 shown in FIG. 8A is the belt regulating member 6 of this embodiment, and as shown in FIG. Located on the upstream side, the tapered portion apex 67 on the downstream side is at the same position as the belt running surface outlet 68b.

On the other hand, the belt regulating member 6 shown in FIG. 8B is the belt regulating member 6 of the comparative example, and as shown in FIG. , and the tapered portion apex 67 on the downstream side is also at the same position as the belt running surface outlet 68b.

FIG. 11 is an explanatory diagram of the printing durability of the fixing belt in the first embodiment.

FIG. 11(a) shows the mounting angle and the number of belt durability (fixing number) when the belt regulating member 6 of this embodiment shown in FIG. 2 shows the relationship between the belt 2 (printing endurance number of sheets).

FIG. 11(b) shows the mounting angle and the number of belt durability ( 10 shows the relationship between the number of sheets of printing permanence of the fixing belt 2).

11A and 11B, the belt regulating member 6 of this embodiment shown in FIG. When the fixing belt 2 positively abuts against the apex of the portion, the mounting angle range in which the fixing belt 2 can ensure the printing durability until its life is wider than in the comparative example.

The reason for this will be described below with reference to FIGS. 8 and 9 using the explanatory view of the operation of the fixing belt in the first embodiment of FIG. 13. FIG.

FIG. 13(a) shows the behavior when the fixing belt 2 hits the tapered portion vertex 64 on the upstream side of the belt regulating member 6 of the comparative example shown in FIG. 8(b).

The end surface of the rotating fixing belt 2 contacts the inclined surface of the extension portion 62, and the contact pressure with the inclined surface of the extension portion 62 increases.

Since the upstream tapered portion apex 64 is at the same position as the belt running surface entrance 68a (see FIG. 10(a)), it contacts the inclined surface of the extension portion 62 as shown in the upper diagram of FIG. 13(a). Buckling deformation (turning up) occurs when the end face of the fixing belt 2 rotating while hitting the tapered portion apex 64 .

The buckling-deformed end surface of the fixing belt 2 cannot escape to the inside (inner peripheral surface side) due to the belt running surface 68, and cannot be deformed toward the belt running surface 68 side. It spreads and turns over.

As shown in the lower diagram of FIG. 13A, the fixing belt 2 that has spread outward (on the outer peripheral surface side) is subjected to a local force applied to the end portion by the tapered portion apex 64, and at the same time, the spreading force (D1, D2) will work, and even if the biasing force is smaller than the strength S, cracks may occur and damage may occur.

In this way, the end of the fixing belt 2 is repeatedly turned over during rotation, and the end is spread over the trumpet, causing fatigue fracture (breakage).

When the fixing belt 2 abuts against the apex 67 of the tapered portion on the downstream side of the belt regulating member 6, the end of the fixing belt 2 is similarly repeatedly turned up during rotation, and the end is spread on the trumpet. Fatigue fracture (fracture) occurs.

On the other hand, FIG. 13(b) shows the behavior when the fixing belt 2 hits the upstream tapered portion apex 64 of the belt regulating member 6 of this embodiment shown in FIG. 8(a).

The end surface of the rotating fixing belt 2 contacts the inclined surface of the extension portion 62, and the contact pressure with the inclined surface of the extension portion 62 increases. At this time, the buckling deformation (turning up) of the end surface of the fixing belt 2 is maximized near the apex 64 of the tapered portion.

Since the upstream tapered portion apex 64 is located further upstream than the belt running surface entrance 68a (see FIG. 10A), the fixing belt 2 is tapered as shown in the upper diagram of FIG. 13B. When it hits the apex of the part, buckling deformation occurs and it bends inward (inner peripheral surface side).

More specifically, curling occurs at the end of the fixing belt 2 on the upstream side of the tapered portion vertex 64 , and the curling is maximized near the tapered portion vertex 64 . Since the fixing belt 2 does not exist, the edge of the fixing belt 2 is bent inward (toward the inner peripheral surface) in an attempt to return to its original state.

The reason why the end portion of the fixing belt 2 bends inward (toward the inner peripheral surface) is that there is no belt running surface 68 inside the apex 64 of the tapered portion, and buckling deformation is caused by a weaker force for bending inward than expanding outward. This is because expansion to the outside restricts deformation.

After that, in the region where the belt running surface 68 exists, the inner peripheral surface of the fixing belt 2 is supported by the belt running surface 68, and the inside (inner peripheral surface side) of the end portion of the fixing belt 2 is eliminated. Become.

Thus, in this embodiment, in the rotation direction of the fixing belt 2, the tapered portion apex 64, which is the terminal point of the inclined surface of the extension portion 62 of the belt regulating member 6, is the belt running surface entrance 68a, which is the starting point of the belt running surface 68. Since the fixing belt 2 is provided on the upstream side, the fixing belt 2 contacts the tapered portion apex 64 before the belt running surface entrance 68a. Deformation is restored, and breakage of the fixing belt 2 can be suppressed.

As described above, in the first embodiment, it is possible to suppress damage to the fixing belt.

The configuration of the second embodiment differs from that of the first embodiment in the configuration of the belt regulating member.

The configuration of the second embodiment will be described with reference to FIG. 14, which is a perspective view of the belt regulating member in the second embodiment, and FIG.

Parts similar to those of the above-described first embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

As shown in FIGS. 14 and 15, the tapered extension 62 on the upstream side in the belt rotation direction forms a tapered portion apex 64 at the boundary of the belt regulating surface 61, and is further upstream than the belt running surface entrance 68a. located on the side. This is the same as the first embodiment.

In this embodiment, the downstream tapered portion apex 67 is located further downstream than the belt running surface outlet 68b.

That is, the tapered portion apex 67, which is the starting point of the inclined surface of the extension portion 66, is provided downstream from the belt running surface exit 68b, which is the end point of the belt running surface 68, in the belt rotation direction.

The operation of the configuration described above will be described.

Note that the operation of the image forming apparatus is the same as that of the first embodiment, so the explanation is omitted.

FIG. 16 is an explanatory diagram of the printing durability of the fixing belt in the second embodiment.

FIG. 16 shows the mounting angle and the number of belt durability (printing durability of the fixing belt 2) when the belt regulating member 6 of this embodiment shown in FIG. ).

As shown in FIG. 16, in the belt regulating member 6 of this embodiment shown in FIG. 14, the fixing belt 2 hits the tapered portion vertex 67 of the belt regulating member 6 not only on the positive side but also on the negative side. In this case, the range in which the fixing belt 2 can ensure the print durability until the end of its life is wider than in the first embodiment. In other words, the mounting angle tolerance of the belt regulating member 6 has a margin.

As described above, in the second embodiment, in addition to the effect of the first embodiment, the effect of allowing the mounting angle tolerance of the belt regulating member to have some margin can be obtained.

In the first and second embodiments, the image forming apparatus is described as a printer, but the present invention is not limited to this, and is a copying machine that forms black-and-white (monochrome) images or color images of at least two or more colors. , a facsimile machine, a multifunction peripheral (MFP), or the like.

Reference Signs List 1 fixing roller 2 fixing belt 3a, 3b support 4 planar heating element 5a, 5b pressure member 6 belt regulation member 7 nip forming member 8 pressure roller 10 image forming device 11 fixing device 13 developing device 14 image carrier 15 charging Member 16 latent image forming means 17 developing means 18 transfer member 61 belt regulating surface 62, 66 extended portion 63, 65 edge portion 64, 67 tapered portion vertex 68 belt running surface 68a belt running surface entrance 68b belt running surface exit

Claims (7)

a rotatable belt-shaped fixing member;
a regulating member for regulating a side end portion in the rotation direction of the stretched fixing member;
has
The regulation member is
a guide portion that contacts a portion of the inner peripheral surface of the fixing member in the rotational direction;
a regulating portion that regulates the movement of the side end portion of the fixing member that contacts the guide portion;
an upstream inclined portion extending upstream of the restricting portion in the rotational direction and having an inclined surface inclined in a direction away from the fixing member;
has
The fixing device, wherein the end point of the inclined surface of the upstream inclined portion is provided upstream from the starting point of the guide portion in the rotational direction. The fixing device according to claim 1,
the guide portion has a contact surface that contacts an inner peripheral surface of the fixing member;
The fixing device according to claim 1, wherein the restricting portion has a wall surface that is perpendicular to the contact surface and abuts against a side end portion of the fixing member to restrict movement of the fixing member. In the fixing device according to claim 1 or 2,
An inclined surface of the upstream inclined portion is continuous with the restricting portion, and is formed so as to be inclined in a direction away from the fixing member from the downstream side to the upstream side in the rotation direction. Device. In the fixing device according to any one of claims 1 to 3,
The regulation member is
a downstream inclined portion extending downstream of the restricting portion in the rotational direction and having an inclined surface inclined in a direction away from the fixing member;
The fixing device according to claim 1, wherein a starting point of the inclined surface of the downstream inclined portion is provided downstream of an end point of the guide portion in the rotational direction. The fixing device according to claim 4,
An inclined surface of the downstream inclined portion is continuous with the restricting portion and is formed so as to be inclined in a direction away from the fixing member from the upstream side to the downstream side in the rotational direction. Device. In the fixing device according to any one of claims 1 to 5,
The fixing device, wherein the regulating member is arranged to face the fixing member with the fixing member interposed therebetween. An image forming apparatus comprising the fixing device according to claim 1 .

Images